Tijuana, Mexico; and Hidalgo, Texas — Editor's note: The Monitor published this story in May 2016, when Donald Trump was the presumed candidate for the Republican Party. Today, President Trump signed an executive order authorizing construction of a wall along the US-Mexico border. Here's how people living along that border view the idea.

Seven-year-old Manuel stands on a pile of dirt that abuts his backyard fence and briskly hoists up one leg, straddling the corrugated-metal. His little sister, pacifier in mouth, giggles at her brother’s antics.

Despite the fun, Manuel’s backyard is far from typical. In fact, the fence he’s crawling over is an international barrier, dividing his informally built community of La Libertad, or Liberty, in Tijuana, from the United States.

He and his family live in one of the last houses in this neighborhood that's right up against the wall: open the back door and the fence stands about a foot away. The homes were there before the wall, neighbors say, reminiscing about a baseball diamond that’s now in the grassy, trash-strewn no-man’s land on the other side.

Denise, Manuel’s mom, says she’s already been informed her house will be torn down in the next year for security reasons. It’s stressful to think about a move, but there are some things she won’t miss, like a US Border Patrol camera watching over their home, or the sporadic visits by Mexican police responding to Border Patrol calls that someone was spotted trying to cross nearby – usually late at night.

With Donald Trump emerging this month as the presumed Republican presidential candidate, his promises to build up the US-Mexico border wall are increasingly hard to ignore. Aside from the many issues surrounding how the wall would be financed, the possibility of an expanded border fence also raises questions of what it would look like, and how it would affect families or cross-border communities.

The US-Mexico border is often referred to as a singular entity – The Border, The Wall, The Fence. But, at present, the wall is far from a continuous structure, and each community and region along the nearly 2,000-mile expanse of shared boundary provides a different perspective on what a physical division between the two countries means in practice.

From neighborhoods built so close to the international dividing line that kids grow up viewing the structure as a jungle gym, to tight-knight communities and families split in two by the wall’s construction, to migrants who see little more than an obstacle to overcome: the implications of a more complete or “secure” border fence are complicated and diverse. And beyond the discussion of security and migration, these communities already living with a wall offer lessons on what a dividing structure can – or cannot – do in practice.

Cat-and-mouse game

Police Lt. Jesus Ortega and Officer Rene Perez cruise by the border wall in Hidalgo, a town of roughly 13,000 in the Rio Grande Valley. Mr. Perez slows the official vehicle every now and then to accommodate a morning jogger or bike rider using the paths parallel to the border wall.

Four hand-made ladders piled up along the US side of the barrier indicate some high-adrenaline exercise by migrants, too. The ladders, which Perez describes as “built better than [what] they sell at Lowes,” have been gathered by local police and Border Patrol agents and will be destroyed, the officers say.

“In my personal opinion, the wall has had very little impact here,” says Mr. Ortega, who monitors the area with colleagues in support of the Border Patrol. The multi-sectioned wall of concrete and large, rust-red slabs of metal was completed about six years ago. Standing as high as 18 feet tall, at some points it’s situated as far as a half-mile or more from the Rio Grande, which naturally divides the US and Mexico.

“Before, patrols could see people coming,” Ortega says, referring to looking out across the riverbanks. “Now, it’s a new kind of cat-and-mouse game,” he says, estimating that between 20 and 100 people try to cross illegally in Hidalgo each day.

The Rio Grande Valley has a long history of families living on both sides of the international divide, flowing fluidly back and forth between both countries. For those who aren’t simply using the region as a one-time point of entry into the United States, there’s a common phrase to describe border life here.

“We don’t cross the border. The border crosses us,” says Paula Garcia, executive director of Teach for America in the Rio Grande Valley. Like many families in the region, she has loved ones on both sides of the border, or with different citizenship statuses.

One of the most visible representations of this idea, of the border barreling through to divide communities and families, and their efforts to keep living life as usual, is in the public school system. Scores of kids who walk and cycle to the local elementary and high schools here include an international border crossing in their daily commute.

One 16-year-old high school freshman, Angie, estimates on a recent misty Wednesday morning that roughly 40 percent of her class crosses over from Mexico to attend school each day. The students are US citizens, but often times a parent or another sibling in the family isn’t. Her address that makes her eligible to go to school in the US belongs to a relative that lives in the area, and Angie spends a few nights a week sleeping at her home.

“I’m changing my future,” Angie says, passing the bustling elementary school carpool lane on her way to first period. “I have more goals here. I’ve learned English, I can play sports, the class periods last longer,” she says.

The nearby public school district of Progreso saw a similar phenomenon of students crossing, and has been caught up in a legal battle with the state over student residency requirements. The Texas Education Agency accused the district of allowing Mexican residents into the district in order to increase enrollment numbers and claim more state education funding.

For Angie, the decision to start going to school in the US was an easy one. “I want to go to college,” she says, and the wall is just an extra stop along the way. “I’m here to learn. I can’t come to school in the US and not try.”

Jose stands in front of an altar he built on the boder fence in La Libertad, an informally-built community that stands against the border fence between Mexico and the United States in Tijuana, Mexico.Jika Gonzalez

In Mexico’s western state of Baja California, the wall takes on a dizzying array of shapes and sizes. In the small community of Jacumé on a recent afternoon, kids wander the central square dressed as wobbly renditions of lady bugs, cowboys, and ducklings for the annual spring festival. Carol, who grew up here, says the repercussions of 9/11 – and the emphasis put on securing US borders – changed her community drastically.

What used to be an informal crossing with a lone border patrol agent or two between her town in Mexico and the one where her mother and brother live in the US in the past took about 20 minutes door-to-door. After the 2001 terrorist attacks, a physical wall, about 10 feet tall, was built here. There’s no place to cross legally, and now she has to drive to the closest formal border crossing, making the trip to mom’s 2-1/2 to 3-1/2 hours.

“Everything on the other side affects us here,” says Carol, referring to the United States.

About a mile to the north, a steep hill, strewn with spindly cactuses and the random shoe or weathered backpack, dead ends into the squat border wall. A poem is scribbled on the sloped fence:

“Go north, work and be prosperous. Make a better place for all, but don’t forget where you came from. Be anxious to come back and help your brothers and sisters when the time of change comes.”

The US-Mexico border wall “has a different psychological impact depending on where you are situated around it and what your economic class is in relation to it,” says Fonna Forman, who teaches political science at the University of California, San Diego and directs the Center on Global Justice.

“The majority of people on the southern side have difficulty crossing, and the impact that that has on feelings of self worth is difficult to grasp. When you think about what it means to be a child growing up on the other side of a wall and seeing this fence separating you from what you’re told is the land of opportunity, wealth, and privilege: it can have a damaging effect.”

'Planting seeds of hate'

Blanca, a mother of four, sits smiling on the cozy sectional at the Instituto Madre Assunta women’s shelter in Tijuana. She’s crossed back and forth between Mexico and the US at least 12 times in her life, first arriving in California 30 years ago at the age of 15.

She and her husband started a family and moved across the country for undocumented work: ranching in California, picking apples and pears in Washington State, cleaning homes in Arizona, and eventually settling into Colorado with their kids, three of whom are US citizens. She went back to Mexico two years ago to take care of some land she’d inherited, only to realize returning to her family in the US had become much more complicated due to increased border controls.

She applied for a visa and was denied. Blanca’s voice changes as she tells her story of separation, of being kidnapped while trying to cross clandestinely through the mountains in California and watching as her captors called to demand $6,500 in ransom from her husband, which he paid.

She doesn’t start to cry until she talks about another failed border crossing, when a US agent pulled her aside and asked briskly, “Why are you trying to sneak into my country? Don’t you know it’s a crime?” She lost it, she says, telling the agent she’d never risk it if she had the safety and security he lived with every day.

“When I see the wall,” Blanca says, “all I feel is sadness.”

Her eyes narrow at the suggestion that the wall needs to be extended to better keep people like her out – and at Mexico’s expense.

“The wall. This Mr. Trump,” she says. “They are planting seeds of hate, and it grows in our hearts.”